The commercial application of lipases (esterases) from animal origin are varied. For example, these enzymes find utility in natural flavor production such as in enzymatic modification of lipid food ingredients and in cheese ripening processes by shortening the cheese aging time. The lipases are also useful for the formation of enzyme modified cheese flavor in the production of certain Italian type cheeses such as provolone. They also find utility in butter fat modification, for developing products which are useful in bakery/cereal products, imitation dairy products, margarines, salad dressings and pizza sauces.
The development of flavor in cheese under storage conditions is attributed to a combination of breakdown of products from milk constituents, mostly from fat. The presence of free butyric acid, caproic acid and capric acids in aged cheese is largely due to the action of lipases on cheese fat. Thus, the cheese-ripening time and the flavor profile can be altered by the amount of available lipase in the cheese. Lipases have been extensively used in the production of enzyme modified cheese (EMC). Lipolysed milk fat flavored dairy products are produced by incubation of a pregastric lipase with butter fat or vegetable oils. The resulting hydrolysate is then used as a flavor booster in food products.
Animal lipases have been historically used to enhance the flavor in non-dairy products. The increasing demand for animal lipases in food and dairy industries necessitates the development of an improved processing technology for obtaining higher yields from the limited supply of animal sources.
Animal lipases are typically obtained by drying and grinding calf, kid or lamb gullets to provide a solid, enzyme containing product in which the enzyme is closely associated with the gullet tissue. When used, such as in the making of enzyme modified cheese, the ground gullet bearing the enzyme is added to the vat and blended into the cheese milk. This method suffers from the disadvantage of providing pockets of lipase activity due to the incomplete mixing of the solid lipase containing gullet tissue and the liquid cheese milk. In U.S. Pat. No. 2,531,329 there is disclosed a method for extracting lipase from animal tissue (gullet) using an aqueous solution containing 10% propylene glycol together with sodium chloride at an acidic pH (pH 6.2-6.5).
The advantages of a liquid form of animal lipase are apparent, and it is an object of the present invention to provide such lipase in the liquid form as well as a method for its preparation. A further object is to provide such a method which provides for the extraction of lipase using an alkaline, aqueous medium which does not require additives to enhance extractions by the aqueous medium.